Yuan M, Aucken H, Hall L M, Pitt T L, Livermore D M
Antibiotic Group, Department of Medical Microbiology, St Bartholomew's and the Royal London School of Medicine and Dentistry, Whitechapel Site, London, UK.
J Antimicrob Chemother. 1998 May;41(5):527-39. doi: 10.1093/jac/41.5.527.
Extended-spectrum beta-lactamases (ESBLs) are an increasing cause of resistance to oxyimino-aminothiazolyl cephalosporins, especially in klebsiellae. In a recent survey we detected ESBLs in 220 (23%) of 966 consecutive klebsiellae from 35 intensive care units (ICUs) in southern and western Europe. The present study examined the extent to which this distribution reflected epidemic strain spread, as against the distribution of ESBL genes into unrelated strains. All 220 ESBL producers were subjected to capsular serotyping and pulsed-field gel DNA electrophoresis (PFGE). Beta-Lactamases were typed for strains isolated on three or more occasions, with the emphasis on SHV enzymes, as these were commoner than TEM variants. Serotyping and PFGE typing defined 85 distinct strains, from 23 of the 35 participating centres. Of 14 centres that contributed five or more ESBL producers, all sent representatives of more than one strain, and two centres sent members of ten or more different strains in contributions of 17-21 ESBL-producing isolates. Nevertheless, epidemic strains-defined as those represented by three or more isolates-accounted for a majority (61%) of the collection. Fifty-two isolates of the same serotype K25 (occasionally acapsular) strain with SHV-4 beta-lactamase were recovered at two French hospitals and one in Belgium. This strain has been found by others in France, and has become particularly widespread. Another single strain was found in two separate Portuguese centres, and many individual hospitals had one or more epidemic strain(s), as well as a scatter of diverse ESBL producers. Major variation in antibiogram and plasmid profile was apparent within strains, with some intra-strain variation in beta-lactamase type. These data imply a fluid situation, with resistance determinants being gained, modified or lost. The endemicity of ESBL producers is disturbing since it limits the potential for control by blocking strain spread, while the diversity within strains is disturbing because it complicates the design of antibiotic policies even during 'single strain' outbreaks.
超广谱β-内酰胺酶（ESBLs）是导致对氧亚氨基-氨基噻唑基头孢菌素耐药性增加的一个日益重要的原因，尤其是在克雷伯菌属中。在最近的一项调查中，我们从南欧和西欧35个重症监护病房（ICU）的966株连续分离的克雷伯菌中检测到220株（23%）携带ESBLs。本研究探讨了这种分布在多大程度上反映了流行菌株的传播，以及ESBL基因向无关菌株中的分布情况。对所有220株产ESBLs菌株进行了荚膜血清分型和脉冲场凝胶DNA电泳（PFGE）。对分离三次或更多次的菌株进行β-内酰胺酶分型，重点是SHV酶，因为它们比TEM变体更常见。血清分型和PFGE分型确定了来自35个参与中心中23个中心的85个不同菌株。在提供5株或更多产ESBLs菌株的14个中心中，所有中心都送来不止一个菌株的代表，两个中心在提供17 - 21株产ESBLs菌株时送来10个或更多不同菌株的成员。然而，被定义为由三个或更多分离株代表的流行菌株占收集菌株的大多数（61%）。在法国的两家医院和比利时的一家医院中分离到52株相同血清型K25（偶尔无荚膜）且携带SHV-④β-内酰胺酶的菌株。其他人在法国也发现了这种菌株，并且它已经变得特别广泛传播。在两个不同的葡萄牙中心发现了另一个单一菌株，许多医院有一个或多个流行菌株，以及一些不同的产ESBLs菌株。菌株内抗菌谱和质粒图谱存在明显差异，β-内酰胺酶类型也存在一些菌株内变异。这些数据表明情况不稳定，耐药决定因素会获得、改变或丢失。产ESBLs菌株的地方性流行令人不安，因为它通过阻断菌株传播限制了控制的可能性，而菌株内的多样性令人不安是因为它使抗生素政策的设计变得复杂，即使在“单一菌株”爆发期间也是如此。 （注：原文中“SHV-④”的④可能有误，推测为常见的“SHV-4”，翻译中按此修正，具体需根据原文准确信息确定）
